From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: X-Spam-Status: No, score=1.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, PDS_BAD_THREAD_QP_64,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H5, RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 Authentication-Results: gnuweeb.org; dmarc=pass (p=none dis=none) header.from=ACULAB.COM Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=185.58.86.151; helo=eu-smtp-delivery-151.mimecast.com; envelope-from=david.laight@aculab.com; receiver= Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by gnuweeb.org (Postfix) with ESMTPS id D27E824B392 for ; Fri, 1 Sep 2023 21:23:36 +0700 (WIB) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mtapsc-3-upz6m7wVOF-ZST2cWmMt8w-1; Fri, 01 Sep 2023 15:23:33 +0100 X-MC-Unique: upz6m7wVOF-ZST2cWmMt8w-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Fri, 1 Sep 2023 15:23:28 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Fri, 1 Sep 2023 15:23:28 +0100 From: David Laight To: 'Ammar Faizi' , Willy Tarreau CC: =?iso-8859-1?Q?Thomas_Wei=DFschuh?= , "Nicholas Rosenberg" , Alviro Iskandar Setiawan , Michael William Jonathan , GNU/Weeb Mailing List , Linux Kernel Mailing List Subject: RE: [RFC PATCH v1 0/5] nolibc x86-64 string functions Thread-Topic: [RFC PATCH v1 0/5] nolibc x86-64 string functions Thread-Index: AQHZ23UUaWogkrxxpUapKlllYL+KVbAF2IcQgAAa01yAABQxQA== Date: Fri, 1 Sep 2023 14:23:28 +0000 Message-ID: References: <20230830135726.1939997-1-ammarfaizi2@gnuweeb.org> <5a821292d96a4dbc84c96ccdc6b5b666@AcuMS.aculab.com> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable List-Id: From: Ammar Faizi > Sent: 01 September 2023 14:06 ... > > You're completely right indeed, reminds me about the copy_up/copy_down > > that were not used anymore :-) >=20 > I'm an idiot, will fix that. Another attempt as suggested below: >=20 > __asm__ ( > ".section .text.nolibc_memmove\n" > ".weak memmove\n" > "memmove:\n" > " movq %rdx, %rcx\n" > " movq %rdi, %rdx\n" > " movq %rdi, %rax\n" You seem to have confused yourself about whether you are using %eax or %edx= . > " subq %rsi, %rdx\n" > " cmpq %rcx, %rdx\n" > " jnb .Lforward_copy\n" I think I'd fall through to the forwards copy and not worry about replicating the 'reps movsb' and 'ret'. IIRC 'cld' can be slow as well. > " leaq -1(%rdi, %rcx, 1), %rdi\n" > " leaq -1(%rsi, %rcx, 1), %rsi\n" > " std\n" > ".Lforward_copy:\n" > " rep movsb\n" > " cld\n" > " ret\n" > ); >=20 > -- > Ammar Faizi =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)